Vehicles with hybrid drive of various different implementations have in specific drive cycles a more advantageous consumption performance than vehicles, which are solely driven by a combustion engine. Therefore, they are gaining importance in the market.
If an electric machine is used as second drive means, this can be used as a motor and a generator. In the motor function, which necessitates the power supply by a battery, a starting of a combustion engine or a use as a driving motor is possible. When used as a generator it serves for recharging the battery, wherein the power can be drawn from the combustion engine or from the recuperation of kinetic vehicle energy.
If a flywheel mass system is used as second drive means, these can be used for energy storage during deceleration of the vehicle and for the power output during the acceleration of the vehicle. An energy storage can also be achieved by the combustion engine.
In so far as an electric machine and a flywheel mass system are combined to second means, additional operating modes are possible, e.g. the acceleration of the flywheel mass system by the electric machine during standstill of the vehicle and a joint energy output by the flywheel mass system and the electric machine during vehicle acceleration.
From US 2005/0101432 A1 a hybrid drive system of the above named type is known. A hybrid drive system with an automatic mechanical transmission (AMT), which comprises two shiftable partial transmissions and which enables a large number of operating conditions, is known from WO 2008/138387 A1. The arrangement of the drive means on the transmission shafts is, in this case, especially advantageous for the application as a transversal installation in a motor vehicle, thus, especially for the combination with transversally installed combustion engine, which crank shaft is, thus, arranged transversally to the motor vehicle longitudinal direction. Hybrid drive systems are, furthermore, described for example in WO 2005/073005 A1, DE 100 49 514 A1 and DE 198 18 108 A1.
From DE 199 60 621 A1 a hybrid drive for vehicles with a shiftable transmission is known, which comprises a first shiftable partial transmission, which is selectively drivingly connectable to a fuel engine and/or an electric machine, and comprises a second shiftable partial transmission, which is drivingly connected to the electric machine, which can be operated as an electric motor or a generator. The first partial transmission comprises a first countershaft and an output shaft and has six gear steps; the second partial transmission comprises a second countershaft and the same output shaft and has three gear steps.